Tire Test - Surly Larry 27 TPI

Test Summary

Compare up to 3 tires

The Surly Larry is available in both a folding bead 120 TPI and a wire bead 27 TPI version. Because the price difference between these versions is quite large, it's interesting to compare both and see how much you're losing when going with the cheaper version. When looking at the specifications of both the 120 TPI and 27 TPI versions, the most obvious difference is the much higher weight of the cheaper version: 1567 grams Vs 1256 grams.

Except for the much higher weight of the 27 TPI version, both versions appear to be identical when fitted to the bike. The only thing that makes it clear you're running the 27 TPI version is the small "27 tpi" printing on the sidewalls of the tires. Unfortunately, Surly doesn't give a lot of technical details about their tires. I couldn't find any info about the compounds used on these tires, so I'm not sure if the differences seen in the tests come from the casing or the compound.

As mentioned before, the biggest difference is the much higher weight of the 27 TPI version. After measuring both tires, the difference is even bigger as my sample of the 120 TPI version came in below the specified weight and the 27 TPI version came in quite bit heavier than the specified weight: 1660 grams Vs 1567 grams. When fitting both the 120 TPI and 27 TPI version on a 65 C rim, inflated to 16psi, the 27 TPI version ends up slightly bigger with a max casing width and height of 95 and 81 mm (the 120 TPI Larry came in at 93 and 80 mm).

After measuring the thickness of the casing of both tires, it becomes clear why the 27 TPI carries that much more weight: the sidewalls and tread section of the 27 TPI Larry are much thicker. The sidewalls of the 27 TPI version have a thickness of 1.3 mm (120 TPI = 0.9 mm). The tread section of the tire has a thickness of 2.9 mm (120 TPI = 2.5 mm). The height of the knobs is the same for both the 27 and 120 TPI versions.

Use the formula: RR (watts) = CRR * speed (m/s) * load (N) to calculate rolling resistance at a given speed and load

As expected, the 27 TPI version has a higher rolling resistance than the more expensive and lighter 120 TPI Larry (read review), but the disadvantage isn't as big as I had expected. On average, it appears rolling resistance of the 27 TPI Larry is close to 10 - 15 % higher across the different air pressures.

While rolling resistance isn't that much higher than the 120 TPI Larry, it must be said the 120 TPI Larry didn't perform that well in the rolling resistance test in the first place. When comparing the 27 TPI Larry with the much faster Schwalbe Jumbo Jim, rolling resistance is close to 50% higher.

Puncture Resistance Test Results

Puncture Resistance Test Result (higher is better)

Puncture Resistance Tread

5

Puncture Resistance Sidewall

4

In the puncture resistance tests, the 27 TPI Larry scores nearly the same as the 120 TPI Larry in both the tread and sidewall tests.

Conclusion

Just like the 120 TPI version of the Larry, I'm not impressed by this cheaper 27 TPI version. Weight is way too high for me to consider this tire and to make matters worse, comes in over the specified weight by nearly 100 grams. I can't recommend this tire because even though this is a cheaper alternative to the 120 TPI Larry, it's more expensive than other top of the line, better performing tires from other manufacturers.